Conventionally, there is a technology in which the feature amount of an object is extracted from image data obtained by photographing the object and the extracted feature amount is compared with the prepared data indicating the feature amount of a registered each reference object to recognize the category of the object. Moreover, a store system in which such technology is applied to the recognition (identification) of a commodity such as vegetables and fruits and the sales of the recognized commodity is registered is proposed. In such a store system, in a case in which there are a plurality of commodities (commodity candidates) serving as a recognized candidate for the commodity, the commodity candidates are displayed in the descending order of similarity degree with the commodity and a selection operation for the commodity candidates from an operator is received.
However, in the conventional constitution and operation stated above, the display order of the commodity candidates is interchanged in a case in which a commodity candidate having a similarity degree higher than that of the commodity candidate presently displayed is recognized even in a case in which one commodity is held over against a reading window because the commodity candidates are displayed in the descending order of similarity degree. In this case, if the display order of commodity candidates is suddenly interchanged at the timing an operator just selects a commodity candidate displayed, there is a possibility that the operator inadvertently selects a commodity candidate which is not desired. Thus, a technology is needed to avoid such an incorrect selection.